Lower GI bleeding

Bleeding originating distal to the ligament of Treitz

• Often colloquially used to mean colonic bleeding

Aetiology (40% have two potential lesions)

Colonic (95%)

• • Anatomic (painless, large-volume)
    • Diverticulosis (30-40%)
      • As the dome of the diverticulum forms, the vessel entering at that point becomes stretched and can rupture
      • Bleeding usually occurs in the absence of diverticulitis
      • Right colon is the source of bleeding in >50% of patients (usual demographics)
      • Resolves spontaneously in 80% overall and 98.5% of those receiving <4 units pRBC per day. 10% will rebleed within a year and nearly 50% within 10 years.
      • Intervention generally considered necessary if >6U pRBC per day
        • IR - 85% success rate, low rate of re-bleeding
        • Colonoscopy
          • Treat if there are stigmata of recent haemorrhage - visualised bleeding, exposed blood vessel, adherent clots
          • Dual modality: can use adrenaline, coagulation, APC, and fibrin glue
          • Clipping safer than bipolar (risk of perf), and also marks area
          • Tattoo area?
        • OT (last resort)
      • Up to a third recur within a year
    • Aorto-enteric fistula
      • Suspect if previous aortic surgery
  • Vascular (painless, large-volume)
    • Angiodysplasia aka AVM/angiectasias/vascular ectasia (3%)
      • Acquired degenerative lesions secondary to progressive dilatation of normal submucosal blood vessels due to venous obstruction - distinct from true congenital AVMs
      • Can occur anywhere in the GIT, but most commonly caecum
      • Painless/mild cramping. Episodic venous bleeding. Increased prevalence in elderly. Often right colonic/caecal.
      • 90% resolve spontaneously - but can recur
      • Associated with aortic stenosis, CCF, end-stage CKD, von Willebrand's disease, left ventricular assist devices
      • Colonoscopy
        • APC is best, but can also be treated with bipolar electrocoagulation or heater probe
        • Incidentally-discovered lesions do not require any further treatment
      • IR 50% success rate
      • Thalidomide and octreotide have demonstrated efficacy in treating chronic angiodysplastic bleeding
  • Colitis/proctitis - most often associated with pain and diarrhoea
    • IBD (3-4%)
      • Mostly UC
      • Bleeding almost always from diffuse colitis with no discrete lesions amenable to treatment
      • Exclude infection as cause of bleeding
      • Crohn disease can sometimes produce discrete ulcers that have eroded into a vessel, giving a good target for embolization
      • Very rare for major bleeding to be the initial presentation of either Crohns or UC.
      • Schein recommends total colectomy for major bleeding, as it signifies a failure of medical management.
    • Infectious (3-8%) - separate topic
      • Especially CMV and C. diff
    • Radiation-induced (1-3%) - separate topic
    • Ischaemia (5-10%) - separate topic
  • Neoplastic (5-10%)
    • Responsible for 10% of lower GI bleeding in pts >50
    • Bleeding tends to be minor and sporadic
    • Iron deficiency anaemia
    • GISTs in particular can erode into blood vessels
    • Resect colonic cancers if causing massive bleeding
    • Rectal cancers: attempt to avoid acute resection, which would be difficult and also spoil neoadjuvant therapy. Reasonable to attempt endoscopic first. Then pack the rectum with adrenaline-soaked gauze, which often works. Can then try a few other things in OT via a trans-anal approach if possible. If all else fails, have to resect and accept compromised oncologic outcomes. Chronic bleeding can sometimes be treated with RTx.
  • Miscellaneous anorectal disorders (5-15%)
    • Haemorrhoids - most common cause in young patients
      • External - painful, sporadic, low-volume bleeds with red blood coating stool
      • Internal - painless sporadic, low-volume bleeds with red blood coating stool
    • Anal fissure
      • Tearing pain and bleeding with defaecation
    • Temporise with a big Foley catheter inflated in the rectal vault then tractioned against the anus
    • If operating, prone jack-knife may be better - blood falls away and is easier to suction clear
  • Iatrogenic
    • Post-polypectomy (3-7%)
      • Can usually be treated endoscopically
    • Anastomotic
  • Other/unknown (11-30%)

Small bowel (5%)

• • Angiodysplasias
  • Erosions or ulcers
  • Crohn disease
  • Radiation - see separate topic
  • Meckel diverticulum - separate topic
  • Neoplasia
  • Aortoenteric fistula

Special populations

• HIV +
  • CMV or lymphoma
• Elderly
  • Diverticulosis or vascular lesions
• Young adults
  • Haemorrhoids/fissure
  • Meckel
• Children
  • Fissure or gastroenteritis or intussusception

Presentation

• >90% of melaena originates from proximal to ligament of Treitz, although it can come from small bowel or even colon
• Tends to be less severe and intermittent compared to UGIB
• Right colon bleeding - often dark red, mixed with stool, occasionally melaena
• Left colon - often bright red
• Haematochezia - bright red blood, clots, or burgundy stools
• Abdominal pain, diarrhoea and bleeding: colitis
• Minor LGIB:
  • Anorectal lesions, IBD, infectious colitis, AVM, polyps, malignancy
  • Can generally be managed as outpatients
• Major LGIB:
  • Haemodynamic instability, altered mental status, or need for transfusion
• Massive LGIB:
  • MTP

Principles of management

• Resuscitation as per UGIB topic
  • Can continue aspirin if strong indication, but stop other anticoagulants
• Indications for admission:
  • Can use Oakland score (MDCalc) to predict risk of discharging from ED
• Anatomic localisation to either likely UGIB or LGIB, as per UGIB topic
• Compile patient-specific differential list using demographics, history and examination
  • Need to rule out anorectal causes
• Imaging/endoscopy if indicated
  • Admission CT angio if suspected active haemodynamically significant bleeding. Generally DO have time to scan them.
  • Admission CT PV if suspected colitis
  • Unstable - angioembolization
  • Stable but still bleeding - prep for colonoscopy ('rapid prep' or no prep, but some PEG is better than nothing if they are stable, and it is safe in bleeding patients)
    • Especially useful with suspected diverticular, angioectasia and post-polypectomy bleeds
  • Stable and not bleeding - home with outpatient colonoscopy
  • Still bleeding and imaging/scope options exhausted - manage as per obscure bleeding under UGIB topic

Investigations

• Note that initial Hb is often at baseline as patient is losing whole blood - becomes more diluted over about 24h
• FBE/UEC/LFT/COAG/G+H + other tests of clotting function depending on anticoagulant
• Check for microcytosis suggestive of chronic bleed
• Scans
  • Nuclear scintigraphy with technetium-99m-labelled RBCs: 0.04-0.1mL/min, can also detect intermittent bleeds. However the actual LOCALISATION is sometimes poor, so it shouldn't be used as a guide for resection target. Only gives positive result in 39-45% LGIB.
  • CT angio: 0.3-0.5mL/min in reliable sources, although the range is wider than that and probably depends on the scanner and how well-timed they are with the phases
• Endoscopy - start off with gas and colon, then consider targeting small bowel
  • Likely to be a hard scope - get the most experienced colonoscopist around, and/or the person that did the original procedure, if there was one
  • Bleeding from anus/lower rectum will reflux to at least the rectosigmoid junction
  • Preferably have all haemostasis gadgets available including APC
  • ScopeGuide might help
  • Don't really need to prep - see above
  • Bleeding from a previous polypectomy site - clips if sessile, EndoLoop if pedunculated
  • Anastomotic bleeding - clips or adrenaline
  • Diverticular bleed - attempt to clip the vessel, if not possible, adrenaline
  • Angiodysplasia - APC or (second preference) adrenaline
  • Consider tattooing the bowel distal to the bleeding point, and clip locally for marking

Angioembolisation

• Observe for 3 days afterwards
• Success rates
  • Diverticular bleed 75-100%
  • Angiodysplasia 50% - not as good
• Complications
  • Femoral access site pseudo-aneurysm
  • Colon ischaemia
    • 3% of patients get ischaemia requiring intervention
    • Mostly mild - treat conservatively, monitor closely
  • AKI

Surgery

• Indications
  • Failure of endoscopic and radiologic options
  • 4-6 units blood within 24 hours, or 10 units in an admission
  • Continued bleeding after 72 hours
• Operation
  • If not localised, need to do total colectomy and end ileostomy (20-30% mortality)
    • Ileorectal anastomosis will leak
  • If localised, can do segmental resection
    • Bad idea to guess the segment - don't do it
    • Left side from diverticulosis: resect the bleeding site and then as far as upper rectum. Choose between Hartmann's and anastomosis.
    • Right side: RHC
    • Transverse: Extended RHC
  • Lithotomy, and repeat the proctoscopy/sigmoidoscopy at the start, just in case. Midline laparotomy. Evaluate all small and large bowel for external localising features. Could do an on-table enteroscopy if small bowel seems to have blood.

Prognosis:

• Bleeding stops spontaneously in 85% of patients
• Mortality 2% (5% in >85yo)